Muffler for internal-combustion engine



P. J. CON LIN Sept. 12, 1967 MUFFLER FOR INTERNAL-COMBUSTION ENGINE 2Sheets-Sheet 1 Filed March 22, 1966 INVENTOR. PATRICK J. CONLIN Sept.12, 1967 P. J. CONLIN R FOR INTERNAIrCOMBUSTION ENGINE MUFFLE 2Sheets-Sheet 1' Filed March 22, 1966 INVENTOR. PATRICK J. CONLINATTORNEY United States Patent Ofiice 33405958 Patented Sept. 12, 19673,340,958 MUFFLER FOR INTERNAL-COMBUSTION ENGINE Patrick J. Conlin,Vancouver, British Columbia, Canada,

assignor to Cone Muffler Development Co., Ltd., Vancouver, BritishColumbia, Canada, a corporation of Canada Filed Mar. 22, 1966, Ser. No.536,322 Claims. (Cl. 181-58) ABSTRACT OF THE DISCLOSURE A muffler forinternal-combustion engines comprising a cylindrical hollow body havingdiametrically opposite, identically tangentially disposed inlet andoutlet nipples extending into said body at opposite sides of a dividingwall having a tube extending therethrough whereby the input gases. arecaused to partake of a whirling motion at an asynchronously increasingrate, then to pass through the tube to the opposite side of thepartition and thereafter to asynchronously decrease in the rate ofrotation or whirl in the same direction en route to the outlet port.

This invention relates to mufiler devices for the exhaust ofinternal-combustion engines and more particularly to a muffler deviceembodying improvements over that disclosed in my prior Patent No.3,166,152 granted Jan. 19, 1965.

The principal object of the invention is to provide a mufller in whichthe pulsations of the exhaust gases as received from the engine arefirst asynchronously imposed on each other at an increasing frequencyrate and thereafter, also asynchronously, imposed on each other at adecreasing frequency rate whereby the pulsations tend almost wholly tocancel themselves out with resultant substantially complete eliminationof the vibrations causing the noise of an engine exhaust.

Other objects of the invention are to provide a muiller of the foregoingcharacter which is composed of few parts, all of which are united into aunitary structure, which is much smaller in size for a given volume ofexhaust gases than mufflers presently in common use, which imposes aminimum of back pressure on the exhaust gases, and which is economicalto manufacture.

With the foregoing objects in view, together with such additionalobjects and advantages as may subsequently appear, the invention residesin the parts and in the construction, combination and arrangement ofparts described, by way of example, in the following specification of apresently preferred embodiment of the invention, reference being had tothe accompanying drawings which form a part of said specification and inwhich drawings:

FIG. 1 is a reduced scale, perspective view of a muflier constituting apresently preferred embodiment of the invention,

FIG. 2 is a geratly enlarged, exploded view of the muffler as shown inFIG. 1, taken as though the mufiler had been cut apart on a planecoincident with the center lines of the inlet and outlet port nipplecomponents,

FIG. 3 is a medial sectional view on a slightly smaller scale than FIG.2 taken in the plane including the line 33 of FIG. 1 and extendingtransversely of the center lines of the two port nipple components,

FIG. 4 is a sectional view in the same scale as FIG. 3 taken on thestaggered line 44 of FIG. 1, and

FIG. 5 is a perspective view of a centrally disposed tubular componentof the device.

Referring to the drawings, the muffler body structure 1 comprises acylindrical center body portion 2 formed by a circular, thin metal wall3 having an oval opening 4 extending therethrough through which an inletnipple 5 extends tangentially with respect to the wall 3 from a pointexteriorly of said wall and of sufficient length to permit connection toan exhaust conduit leading from an engine, said nipple extending throughthe wall 3 to a point within the muffler body which is slightly short ofa center medial plane of said body member extending in a directionnormal to the center line of the nipple component The wall 3 at a pointdiametrically opposite the opening 4 is provided with a similar opening6 through which an outlet nipple component 7 extends similarlytangentially to the nipple 5 and in the same direction circularly of thebody wall 3 as the nipple 5, said nipple extending from a point withinthe body which is slightly short of the plane referred to with respectto the inner end of the nipple 5 through the wall 3 and terminatingexteriorly of the wall in a length sufiicient to permit connection of atail pipe or the like if desired. The nipples 5 and 7 are rigidlyconnected to the wall 3 by welding or brazing and preferably disposedwith the axial lines thereof parallel to each other and at leastsubstantially adjacent to a plane which is normal to the axial line ofsaid body at the midlength of said cylindrical portion thereof.

The enclosure of the muffler body is completed by opposed outwardlypointed conical end wall members 8 and 9 having edge portions whichoverlap the edges of the body member 3 and said end wall members arebrazed or welded to the body member 3 to effect a unitary structure ofthe body and the end members. All of the above described body formingcomponents are formed of suitable sheet metal stampings and lengths oftubing and, as noted, are of simple design, wherefore the cost ofmanufacture is kept at a minimum.

The interior of the body structure is divided into two compartments ofsubstantially identical configuration by a center wall member 10comprising a disk of metal of slightly oval configuration which isplaced within the body member 3 so that with respect to the internal endof the inlet nipple 5 it is at the side thereof adjacent the end member8 and with respect to the inner end of the outlet nipple 7 it is at theside of said nipple which is adjacent the end member 9, it being notedparticularly in FIGS. 3 and 4 that the inner ends of the nipples 5 and 7are slightly flattened as at 5 and 7', respectively, to enable thecircumferential edge of the end wall member 10 to be retained within theconfines of the body wall member 3. This partition wall 10 is secured atvarious points along its circumference to the interior surface of thebody member 3 by appropriate spot welds. For identification, thecompartment formed by the wall 10, a portion of the body member 3 andthe end member 8 and which is in communication with the inner end of theinlet nipple 5 will be designated as the inlet compartment 11 and thecorresponding compartment which is in communication with the outletnipple 7 will be designated as an outlet compartment 12.

Communication between the compartments 11 and 12 is afforded by a tube13 of substantially the same diameter as the outlet and inlet nipplesand which is disposed axially of the mufiler body and which extendsthrough an opening 13 in the wall 10 and being welded in place therein.The end 14 of the tube which is disposed in the inlet compartment 11 iscut away at opposite sides as at 15, 15 to form a pair of diametriacllyopposite leg portions 16, 16 which are welded to the inner face of theend member 8. Adjacent the edge surfaces of the end 14, the wall thereofis provided with a plurality of the end member 9 as best shown in FIGS.3 and 4 and adjacent to said end the tube is provided with a pluralityof small holes 19 extending therethrough which are generally similar tothe holes 17 at the opposite end of the tube.

It is again to be noted that the entire mufiler assembly is composed ofwhat is essentially only four different parts, since the two end membersand the nipple components are identical, and that all of the parts areindividually of simple design and capable of economical manufacture.Still further, it is to be noted that all of the parts are weldedtogether to form a construction which for all purposes may be regardedas being integral.

In operation, the exhaust gas entering the compartment 11 through theinlet nipple 5 must exit through the tube 13 to the outlet compartment12 and thence through the outlet nipple 7 to atmosphere. Since the gasenters the v mufiier body tangentially of the wall of the body portion 3the initial motion of the gas within the compartment 11 is circulartherein and since the entrant end of the tube 13 is at the reduceddiameter portion of the conical end wall, the rate of rotation of thegas as it approaches this smaller diameter end gradually asynchronouslyincreases. Since the gas coming from the engine is delivered is apulsating condition deriving from the operation of the engine, thesepulsations within the inlet compartment 12 impose themselves on eachother and tend to cancel each other out. Moreover, since the gas entersthe tube 13 from opposite sides thereof the pulsations also tend furtherto oppose each other and to cancel each other out as they enter thistube. The progress of the gas going through the tube 13 is accompaniedby an intense whirling motion therein deriving from the nature of theentrance of the gas into the inlet chamber 11 and emerging from the end18 of the tube 13; the gas and its whirling motion must be slowed downby reason of gradually reaching the diameter of the body portion 3 inwhich the inner end of the outlet nipple is located. This is also anasynchronous change of rate of the whirling motion of the gas and forall practical purposes, completes the elimination of the pulsation ofthe gas resulting in a uniformly steady and noiseless emission of thegas from the muffler.

Referring now to the holes 14 and 19, the exact manner in which theseholes operate on the whirling gas is admittedly not known. Repeatedexperiments have shown, however, that adding these holes has measurablycontributed to the silencing effect of this muffler. Several theorieshave been advanced and the most probable one seems to be that the holes14, by permitting a portion of the gas to enter the tube radially inaddition to the axial flow therethrough, tend to oppose and reduce thevelocity of rotation of the gas as it traverses the tube 13 and thatsimilarly, the holes 19 permit a portion of the gas traversing the tube13 to escape radially through said holes into the outlet compartment 12and correspondingly assist in further reducing this whirling movement ofthe gas in that chamber or compartment. Additionally, it is probablethat holes 14 and 19 (particularly the holes 14) serve to destroy andtendency to form a vacuum pocket in the gas flow as it changes itsdirection of movement flowing around the thin edge of the tube 13 as itenters the tube at high velocity. As in my said prior patent, there areno baffles or other obstructions to the flow of exhaust gas, wherefore,the possibility of deleterious back pressure is practically eliminated.

While in the foregoing specification there is disclosed a presentlypreferred embodiment of the invention, the invention is not to be deemedto be limited to the precise details of construction thus disclosed byway of example and it will be understood that the invention includes asWell, all such changes and modifications in the parts and in theconstruction, combination and arrangement of parts as shall come withinthe purview of the appended claims.

I claim:

1. In a muffler for internal-combustion engines, a hollow bodycomprising a generally cylindrical center portion having opposed,outwardly pointed conical ends, a partition within said body dividingsaid body into two compartments comprising an inlet compartment disposedat one side of said partition, a portion of the cylindrical body and oneof said ends, and an outlet compartment disposed at the other side ofsaid partition, the remainder of said cylindrical body and the other ofsaid ends, an inlet nipple extending through said cylindrical centerportion of said body and disposed generally tangentially with respect tothe outer diameter of said cylindrical center portion of said body at apoint between the ends of said center portion and communicating with theinterior of said inlet compartment at a point therein adjacent to aplane containing the axial line of said body and disposed normal to theaxial line of said inlet nipple, an outlet nipple extending through saidcylindrical portion in the same tangential direction as said inletnipple at a point spaced from said inlet circumferentially of said bodyand affording communication between said outlet compartment andatmosphere with said outlet compartment, and a conduit means open atboth ends thereof extending through said partition in the axial line ofsaid body affording communication between said compartments.

2. A muffler for internal-combustion engines as claimed in claim 1 inwhich said inlet and outlet nipples are disposed with the axial linethereof disposed substantially in a plane normal to the axial line ofsaid body and substantially at the mid-length of said cylindricalportion of said body, and in which said partition constitutes a fiatplate closely fitting the interior wall of the cylindrical portion ofsaid body and extends from one side of said inlet nipple to the oppositeside of said outlet nipple.

3. A mufiier for internal-combustion engines as claimed in claim 1 inwhich said conduit means through said partition comprises a tube havinga first open end constituting an inlet orifice means disposed adjacentthe apex of the conical end wall of the inlet compartment and a secondopen end constituting an outlet orifice disposed adjacent the apex ofthe conical end wall of the outlet compartment.

4. A mufiler for internal-combustion engines as claimed in claim 3 inwhich said tube includes pluralities of holes extending through the wallthereof adjacent the open ends thereof.

5. A muffler for internal-combustion engines as claimed in claim 3 inwhich said tube has one end thereof fixedly mounted on the conical endwall of said inlet compartment and the midlength portion thereof fixedlymounted in said partition, and in which the end of said tube within saidoutlet compartment is spaced from the conical end wall of said outletcompartment.

References Cited UNITED STATES PATENTS U 447,333 3/1891 Kutsche.

2,455,965 12/1948 Wohlberg 181-67 X 3,166,152 1/1965 Conlin 181-58FOREIGN PATENTS 1,179,716 12/1958 France.

330,104 12/ 1920 Germany.

RICHARD B. WILKINSON, Primary Examiner, ROBERT S. WARD, J Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,340,958 September 12, 1967 Patrlck J. Conl1n It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 2, line 66, for "dlametrlaclly" read dlametrlcally column 3, line59, for "and" read a any t Signed and sealed this 24th day of September1968 (SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

1. IN A MUFFLER FOR INTERNAL-COMBUSTION ENGINES, A HOLLOW BODYCOMPRISING A GENERALLY CYLINDRICAL CENTER PORTION HAVING OPPOSED,OUTWARDLY POINTED CONICAL ENDS, A PARTITION WITHIN SAID BODY DIVIDINGSAID BODY INTO TWO COMPARTMENTS COMPRISING AN INLET COMPARTMENT DISPOSEDAT ONE SIDE OF SAID PARTITION, A PORTION OF THE CYLINDRICAL BODY AND ONEOF SAID ENDS, AND AN OUTLET COMPARTMENT DISPOSED AT THE OTHER SIDE OFSAID PARTITION, THE REMAINDER OF SAID CYLINDRICAL BODY AND THE OTHER OFSAID ENDS, AN INLET NIPPLE EXTENDING THROUGH SAID CYLINDRICAL CENTERPORTION OF SAID BODY AND DISPOSED GENERALLY TANGENTIALLY WITH RESPECT TOTHE OUTER DIAMETER OF SAID CYLINDRICAL CENTER PORTION OF SAID BODY AT APOINT BETWEEN THE ENDS OF SAID CENTER PORTION AND COMMUNICATING WITH THEINTERIOR OF